Apparatus and process for texturizing yarn



NOV. 12, 1968 P, w, LQNGBOTTOM ET AL 3,409,956

APPARATUS AND' PROCESS FOR TEXTURIZING YARN Filed July 5, 1966 FIGB.

FIGZ.

INVENTORS:

PARKER W. LONGBOTTOM KEN NETH L. HUGGINS BY @pWW AT-TORNEY United States Patent 3,409,956 APPARATUS AND PROCESS FOR TEXTURIZING YARN Parker W. Longbottom and Kenneth L. Huggins, Petersburg, Va., assignors to Allied Chemical Corporation,

New York, N.Y., a corporation of New York Filed July 5, 1966, Ser. No. 562,893 12 Claims. (Cl. 28-1) ABSTRACT OF THE DISCLOSURE Continuous filament yarns are texturized by introducing the yarn into a pre-heat chamber in contact with a heated fluid such as steam which directs the heated yar-n into a texturizing chamber having a larger cross section than the pre-heat chamber wherein the flow of the yarn is impeded whereby a yarn plug is established. The heated fluid is discharged from the texturizing chamber in a reverse direction from entry therein through an arrangement of exhaust ports located in the pre-heat chamber wall concentric to the yarn pasage. The exhausted fluid becomes an insulating medium around the pre-heat chamber to prevent heat loss and provide more uniform temperature tures Within said chamber.

This invention relates to a process and apparatus for texturizing yarn. More particularly, the invention relates to a process and apparatus for texturizing yarn which combines the advantages of jet texturizing processes and stuffer box or other crimping by compaction processes.

Several techniques have heretofore been proposed for improving bulk and covering power of continuous filament yarns. According to one techniques, the yarn is deformed mechanically and then heat-set either with or without an after-relaxation step. A representative process illustrating this technique involves the steps of twisting, heatsetting and then back twisting the yarn to a low final twist level. Still another commercial process involves the steps of twisting heat-setting and back twisting on the run, yarn, using a false twisting apparatus. Bulk yarns have also bee-n prepared by the well-known stutfer box technique wherein the yarn is steamed to heat-set while it is in the compressed state in a stutter box. More recently, jet texturizing proceses have come into use which norm-ally utilize a heated compressible fluid, for example, hot air or steam which semiplasticizes the yarn to a crimp receptive condition.

Yarn crimped by the stutfer box method normally does not 'have the covering power of yarn crimped by the jet process as the crimp imparted is not three-dimensional. Advanta-geously, it has been proposed to combine the jet texturizing proces with the stutter box method w'hereby crimped yarns are produced at a high rate and wherein there is imparted to the yarns three-dimensional crimping.

Basically, the apparatus utilized for this combined pr cedure includes an injector which has an internally disposed pasa'ge for yarn. The injector may also be considered a preheat tube since partial heating of the yarn takes place during passage through the tube. Means are provided for supplying a heated fluid under pressure to the injector and in a direction to carry yarn through the injector passage which normally communicates with a crimping chamber wherein the yarn is fed at a rate greater than the take-up rate of the yarn from the chamber so as to allow yarn to build up in yarn plug form at the mouth of the chamber in compressed state thereby receiving a crimp. The fluid most commonly employed is steam which passes through the injector passage and carries with it the yarn, both thereafter entering the crimping chamber under decreased pressure whereby the yarn is heated and crimped and the steam discharged from the chamber through discharge ports located in the central portion of the chamber.

Unfortunately, conventional apparatus for texturizing yarn by this combined procedure, possesses certain inherent disadvantages which makes the production of texturized yarns not entirely satisfactory from apractical commercial standpoint particularly in those cases wherein the yarn is pre-heated during its passage through the injector pasage leading into the stutfer chamber. Design of prior art devices make it difiicult to control and maintain the heat applied to the yarn during passage through the pre-heat tube. Additionally, positioning of the fluid exist means in the stutter chamber whereby the fluid is discharged laterally or co-current with the yarn path, causes the yarn to blow out with the fluid through the exist means.

This invention has for one object to provide improved apparatus for the crimping or texturizing of continuous filament yarn.

Another object is to provide apparatus wherein there is provision for the discharge of treating fluid from the crimping chamber in a direction opposite to the yarn path travel.

Still another object is to provide a process for texturizing yarn which process eliminates the disadvantages of prior art procedures.

Other objects and advantages will be apparent from the following detailed description.

In accordance with the present invention, there is provided a process for texturizing yarn which comprises contacting yarn with a current of fluid, preferably steam, in a pre-heat zone to heat the yarn, directing the yarn under the action of the fluid against a yarn plug contained in a texturizing zone, said zone having a larger cross-sectional area than the cross-sectional area of said pre-heat zone and disposed with relation to said preheat zone such as to form an annulus between the inner periphery of said texturizing zone and the outer periphery of said pre-heat zone, maintaining said texturizing zone under reduced pressure with respect to the pressure in said pre-heat zone, continuously discharging said fluid through said annulus in a direction substantially oppocsite to the direction of yarn path travel through said texturizing zone and continuously dischauging said texturized yarn from said texturizing zone at a lower linear rate than the feed rate of said yarn to said texturizing zone.

In a prefererd embodiment, the yarn to be texturized is directed into a cylindrical pre-heat zone wherein the yarn is contacted with steam at a temperature within the range of about 150 to 500 C. preferably 250 to 450 C. and under pressure maintained in the pre-heat zone of about 5 to 100 p.s.i.g., preferably 5 to 75 p.s.i.g.

Depending upon the conditions of operation, e.g., the type yarn, the temperature and pressure employed, the yarn is reduced to a semi-plastic state and thereafter the yarn is aspirated with the steam into a cylindrical texturizing zone having a larger diameter than the diameter of said pre-heat zone and which is maintained under decreased pressure of about 0 to 15 p.s.i.g. The yarn and steam leave the pre-heat zone and enter the texturizing zone through a nozzle which has conical configuration and a diameter at its apex of substantially the same diameter as the pre-heat zone. The angle of divergence of the walls of the nozzle is within the range of about 20 to preferably 30 to 60, so that the fluid enters the crimping or texturizing zone in the form of a stream with a portion of the stream directed parallel to the longitudinal axis of the texturizing zone and the remaining portions directed at an angle to the axis, the maximum angle of divergence being determined by the angle of the diverging walls of the nozzle. The yarn aspirated into the texturizing zone builds up in yarn plug form in compressed state thereby receiving a crimp. The steam is released from the texturizing zone countercurrent to the path of travel of the yarn and the steam is advantageously 3 employed as an insulating medium around of the pre-heat zone.

Although in a preferred embodiment the steam is released from the texturizing zone substantially opposite to the yarn path travel through the texturizing, and parallel to the longitudinal axis of the texturizing zone, effective results can also be obtained if the steam is released from the texturizing zone at an angle to the longitudinal axis of the texturizing zone within the range of about 135 to 180. Thus, the term substantially opposite as used herein includes steam discharged from the texturizing zone at an angle of 135 to 180 measured on the basis of the longitudinal axis of the texturizing zone and counter-current to yarn path travel.

The process of this invention may be carried out by apparatus which enables thermo-plastic yarn to be texturized at relatively high speeds in the order of 8000 feet per minute or even higher.

The apparatus of the present invention comprises an injector having an internally disposed passage for yarn, fluid inlet means for supplying a heated fluid under pressure through said injector and in a direction to carry yarn through said injector passage, a texturizing chamber eoncentrically disposed at one end of said injector passage and being adapted to contain a compacted yarn mass, said texturizing chamber having a larger cross-sectional area than the cross-sectional area of said injector such as to form an annulus between the outer periphery of said injector and the inner periphery of said texturizing chamber and fluid exit means positioned at said annulus adapted to discharge fluid from said texturizing zone in a direction substantially opposite to yarn path travel.

The process and apparatus of this invention represent a substantial improvement over known methods and equipment for texturizing yarn the manner of carrying it out will be more clearly understood by reference to the drawings in which FIGURE 1 is a sectional view of an embodiment of the apparatus of this invention.

FIGURES 2 through 4 show various types of fluid exit means employed in connection with the apparatus of the invention.

Referring to FIGURE 1, it will be seen that the apparatus includes a housing 10, which supports a portion of an injector or pre-heat tube 11 of substantially cylindrical configuration and which has an internally disposed passage 12. A heated fluid, preferably steam, is introduced into passage 12 through fluid inlet 13 and carries with it, yarn 14 which enters the apparatus through yarn inlet 15.

The velocity of the steam as well as the temperature of the steam is sufficient to carry the yarn longitudinally through the pre-heat tube 11 while rendering the thermoplastic yarp, semi-plastic. For these purposes, there may be employed steam velocities below sonic velocity and temperatures within a range of about 150 to 500 C. "It will be understood, however, that the temperatures selected may be varied and depend upon the type of yarn being processed as well as the pressure within the inlet tube. Generally, pressures within a range of about to 100 p.s.i.g. may be employed without producing detrimental etfects. Disposed at one end of the pre-heat tube is a discharge outlet having a conical configuration, with the apex being disposed immediately adjacent the end of the pre-heat tube and being of substantially the same diameter as the pre-heat tube. We have found that particularly outstanding results are obtained according to the process of the invention when the angle A of the diverging cone 16 at the end of the pre-heat tube is within a range of about 20 to 70", preferably 30 to 60.

Located at one end of the cone or discharge outlet 16 is a texturizing chamber 17 of substantially cylindrical configuration, and which has a larger cross-sectional area than the cross-sectional area of the pre-heat tube 12 so as to form an annulus between the inner periphery of the texturizing chamber 17 and the outer periphery of the preheat tube. A fluid exit plate 19 is located at this position,

the periphery "4 i.e., the annulus, which is provided with slots, holes or a combination of both, the preferred forms being illustrated in FIGURES 2 through 4. The plate is also provided with a cut-out portion 20 as shown in FIGURE 2 which corresponds to the outer configuration of the cone 16.

Referring to FIGURE 2, it will be seen that the plate 11a has a combination of holes' 21 and slot vents 22 terminating at their outer end with axially disposed slots 22a. In FIGURE 3, there is illustrated a plate 1111 which has slots 22a disposed on the periphery of the plate. FIG- URE 4 illustrates a plate having round holes 21a surrounding the cut-out portion 20. The cross-sectional areas of these vent holes or slots are such as to permit eflicient processing depending upon the conditions of operation i.e., denier of the yarns being processed, the fluid pressures and velocities employed and other factors. Merely as illustrative, for texturizing of 2400/ 140 nylon yarn at 3000 f.p.m. using psig. steam at 345 C., the type of plate employed may be as illustrated in FIGURE 2, with a vent hole cross-sectional area of about 0.0.028 square inches.

The fluid is directed into chamber 17 in the form of a stream with the outer periphery of the stream contacting the walls 18 of the chamber 17. The fluid entering the chamber17 with yarn 14 causes the yarn to be impinged against previously advanced yarn in the form of a yarn plug 23 which is maintained in the chamber due to the greater feed rate of the yarn to the chamber against the take-up rate.

The fluid leaves the chamber through the exit plate 19 and advantageously forms an insulating blanket around the pre-heat tube. For this purpose, the walls 18 of the chamber are extended and surround the pre-heat tube 11 and the fluid is discharged therefrom through openings 24.

The yarn plug in the texturizing chamber will change in its density depending upon the residence time in the chamber and the pressures employed therein. Conventional devices may be employed for controlling textured yarn plug length or density such as a gate positioned at the discharge end of the chamber whereby texture level is controlled by changing the weight on the gate, or alternatively, there may be employed a feeler finger in contact with the yarn plug which activates a solenoid valve at desired yarn plug lengths, to increase or decrease the pressure against the yarn plug. The yarn after processing may thereafter be taken up on conventional bobbins using conventional winders, etc.

The process and apparatus of this invention can be used to crimp and bulk any natural or synthetic plasticizable filamentary material. Thermoplastic materials such as polyamides, e.g., poly(epsilon caproamide), poly(hex amethylene adipamide); cellulose esters; polyesters, e.g., polyethylene terephthalate, poly(hexahydro p xylene terephthalate), etc.; polyvinyls and polyacrylics, e.g., polyethylene and polyacrylonitrile, as well as copolymers thereof, can be crimped to give the three dimensional, random, curvilinear configuration described herein.

This apparatus and process are useful for both monofilament yarns in textile deniers as well as the heavier carpet and industrial yarn sizes either singly or combined in the form of a heavy tow. The process and product are :also not restricted in the case of the synthetic materials to any one particular type of filament cross section. Cruciform, Y-shaped, delta-shaped, ribbon, and dumbbell and other such filamentary cross sections can be processed at least as well as round filaments and usually contribute still more bulk than is obtained with round filaments. I

The fluid used to treat filamentary material may be air, steam or any other compressible fluid or vapor capable of plasticizing action on the yarn provided that it has a temperature above the second-order transition temperature of the filament. Hot air will give sufficient plasticiz ation in the turbulent region for many fibers although it may be desirable for certain fibers to supplement the temperature eifect with an auxiliary plasticizing medium.

Actually, steam is preferentially used in the subject process since it is a cheap and convenient source of a high pressure fluid with a compound plasticizing action.

The temperature of the fluid medium must be regulated so that the yarn temperatures do not reach the melting point of the fiber. However, with fibers made from fusible polymers, the most effective bulking and the greatest productivity are obtained when the temperature of the turbulent fluid is above the melting point of the fiber. In this case, the yarn speeds should be great enough so that melting does not occur.

The following examples will illustrate the present invention. EXAMPLE 1 A 2400 denier, 70 filament drawn yarn in the form of a strand, spun from a polycaproamide polymer of formic acid relative viscosity 52 (A.S.T.M.D.789-62T) was delivered to the steam jet texturing apparatus as shown in FIGURE 1, at 3000 feet/minute and at a tension of 50 to 100 grams. The angle A of the diverging cone 16 measured 30. There were 12 equally spaced holes in the rear exhaust which measured 0.0595". Steam at 120 p.s.i.g. and 470 C. temperature was directed from a 0.061 diameter steam nozzle, into a pre-heat tube 4" in length and having .a diameter of 0.125 inch. The yarn strand in the pre-heat tube was heated to a temperature of about 125 C. and the steam and yarn strand were thereafter directed into the chamber where a yarn plug was formed. The steam forced the incoming yarn strand against a slower moving textured yarn plug in the texturizing chamber. The spent steam escaped to the rear through vent holes and provided a blanket of heat around the pre-heater tube. The temperature of the yarn was found to drop by about to 30 C. :as it moved in a compacted mass to the end of the texturizing chamber. After leaving the texturizing chamber, the textured yarn was pulled over several tension bars and wound on a package. The crimp definition of the crimped yarn was: Crimp elongation before boil 10%, crimp elongation after boil and the free shrinkage was 3.0%.

EXAMPLE 2 Yarn was bulked in a a procedure essentially the same as employed in Example 1, except that the feeder yarn was spun and drawn from a /70 blend of polyester and nylon 6 polymers. The angle of the diverging cone 16 measured 30. The polyester polymer had a reduced viscosity (in ortho-chlorophenol containing 0.1% water, at 25 C. and 0.5% concentration) of 0.80 dl./gm. and the nylon 6 polymer had a formic acid relative viscosity of 52 with 19 NH milliequivalents per kilogram and 67 COOH milliequivalents per kilogram. The textured yarn was evaluated and the following properties were determined:

Percent Crimp elongation before boil 10 Crimp elongation after boil 25 Free shrinkage 0.2

Although certain preferred embodiments of the invention have been disclosed for purpose of illustration, it will be evident that various changes and modifications may be made therein without departing from the scope and spirit of the invention.

We claim:

1. A process for texturizing yarn which comprises contacting yarn with a current of heated fluid in a pre-he'at zone to heat the yarn, directing the heated yarn under the action of the fi lid against a yarn plug contained in a texturizing zone, said texturizing zone having a larger crosssectional area than the cross-sectional area of said preheat zone and disposed with relation to said pre-heat zone such as to form an annulus between the inner periphery of said texturizing zone and the outer periphery of said pre-heat zone, maintaining said texturizing zone under reduced pressure with respect to the pressure in said preheat zone, continuously exhausting said' fluid through a plurality of passageways selectively spaced in said annulus in a direction substantially opposite to the direction of yarn travel through said texturizing zone, causing the heated fluid to escape from the texturizing zone through said passageways whereby a major portion of the pre-heat zone is surrounded with said exhausted fluid, and continuously discharging said texturized yarn from said texturizing zone at a lower linear rate than the feed rate of said yarn to said texturizing Zone.

2. A process according to claim 1 wherein the fluid is discharged along paths concentrically spaced around the yarn and parallel therewith to form an insulating medium around said pre-heat zone as the heated fluid is continuously discharged.

3. A process according to claim 1 wherein said fluid enters said texturizing zone in the form of a stream with a portion of the stream directed parallel to the longitudinal axis of said texturizing zone and the remaining portions directed at an angle to the longitudinal axis of said texturizing zone, the maximum angle of divergence from said longitudinal axis being within the range of about 20 to 4. A process according to claim 3 wherein the maximum angle of divergence of said fluid stream is within the range of about 30 to 60 5. A process according to claim 3 wherein said yarn is aspirated into said texturizing zone using steam at a temperature within a range of about 150 to 500 C.

6. A process according to claim 5 wherein said steam is under a pressure of between 5 p.s.i.g. and p.s.i.g. in said pre-heat zone and under a pressure of between 0 p.s.i.g. and 15 ps.i.g. in said texturizing zone.

7. An apparatus for texturizing yarn which comprises an injector having an internally disposed passage for yarn, fluid inlet means for supplying a heated fluid under pressure through said injector passage, 'a texturizing chamber concentrically disposed at one end of said injector passage and being adapted to contain a compacted yarn mass, said texturizing chamber having a larger cross-sectional area than the c-ross-sectionl area of said injector such as to form an annulus between the outer periphery of said injector and the inner periphery of said texturizing chamber and fluid exit means positioned at said annulus adapted to discharge fluid from said texturizing zone in a direction substantially opposite to yarn path travel.

8. Apparatus according to claim 7 wherein said injector has a discharge outlet of conical configuration disposed at one end of said injector leading into said texturizing chamber, said discharge outlet having an apex of substantially the same diameter of said injector and having diverging walls having an angle of divergence within the range of about- 20 to 70.

9. Apparatus according to claim 8 wherein the angle of divergence of the walls of the discharge outlet is within the range of about 30 to 60.

10. An apparatus according to claim 7 wherein said fluid exit means comprises a fluid plate having passageways adapted to per-mitt he discharge of fluid from siad texturizing zone in a direction substantially opposite to ya-rn path travel.

11. Apparatus according to claim 7 wherein a first housing retains the fluid inlet means and a portion of said yarn passage which includes a yarn inlet, and a second housing comprising a texturizing chamber and extended wall concentricllay disposed around a major portion of said ya-rn passage, said extended wall terminating at a distance from said first housing, but in close proximity thereto.

12. Apparatus according to claim 11 wherein the yarn inlet enters the housing at an angle of approximately 45.

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